package database

import (
	"encoding/binary"
	"fmt"
	"net"
	"strconv"
	"strings"
	"time"
)

func IP2Int(ip net.IP) uint32 {
	if len(ip) == 16 {
		return binary.BigEndian.Uint32(ip[12:16])
	}

	return binary.BigEndian.Uint32(ip)
}

func Int2ip(nn uint32) net.IP {
	ip := make(net.IP, 4)
	binary.BigEndian.PutUint32(ip, nn)

	return ip
}

func IsIpv4(host string) bool {
	return net.ParseIP(host) != nil
}

// Stolen from : https://github.com/llimllib/ipaddress/
// Return the final address of a net range. Convert to IPv4 if possible,
// otherwise return an ipv6
func LastAddress(n *net.IPNet) net.IP {
	ip := n.IP.To4()
	if ip == nil {
		ip = n.IP

		return net.IP{
			ip[0] | ^n.Mask[0], ip[1] | ^n.Mask[1], ip[2] | ^n.Mask[2],
			ip[3] | ^n.Mask[3], ip[4] | ^n.Mask[4], ip[5] | ^n.Mask[5],
			ip[6] | ^n.Mask[6], ip[7] | ^n.Mask[7], ip[8] | ^n.Mask[8],
			ip[9] | ^n.Mask[9], ip[10] | ^n.Mask[10], ip[11] | ^n.Mask[11],
			ip[12] | ^n.Mask[12], ip[13] | ^n.Mask[13], ip[14] | ^n.Mask[14],
			ip[15] | ^n.Mask[15],
		}
	}

	return net.IPv4(
		ip[0]|^n.Mask[0],
		ip[1]|^n.Mask[1],
		ip[2]|^n.Mask[2],
		ip[3]|^n.Mask[3])
}

// GetIpsFromIpRange takes a CIDR range and returns the start and end IP
func GetIpsFromIpRange(host string) (int64, int64, error) {
	_, parsedRange, err := net.ParseCIDR(host)
	if err != nil {
		return 0, 0, fmt.Errorf("'%s' is not a valid CIDR", host)
	}

	if parsedRange == nil {
		return 0, 0, fmt.Errorf("unable to parse network: %w", err)
	}

	ipStart := int64(IP2Int(parsedRange.IP))
	ipEnd := int64(IP2Int(LastAddress(parsedRange)))

	return ipStart, ipEnd, nil
}

func ParseDuration(d string) (time.Duration, error) {
	durationStr := d

	if strings.HasSuffix(d, "d") {
		days := strings.Split(d, "d")[0]
		if days == "" {
			return 0, fmt.Errorf("'%s' can't be parsed as duration", d)
		}

		daysInt, err := strconv.Atoi(days)
		if err != nil {
			return 0, err
		}

		durationStr = strconv.Itoa(daysInt*24) + "h"
	}

	duration, err := time.ParseDuration(durationStr)
	if err != nil {
		return 0, err
	}

	return duration, nil
}
